DE19725849A1 - New glass-containing nickel-copper-zinc soft ferrite - Google Patents

Abstract

A novel Ni-Cu-Zn soft ferrite material for making inductors consists of a starting material of 49.0-50.0 mol% Fe2O3, 5-13 mol% CuO, 7.5-25 mol% NiO and 12-38.5 mol% ZnO and additionally contains 0.05-15.0 wt.% B2O3-Bi2O3-ZnO glass. Also claimed are (i) a process for producing a wire coil inductor from the above starting material and glass, preferably employing a binder containing PVA or methyl cellulose as main component; and (ii) a process for producing a chip inductor from the above starting material and glass, preferably employing a binder mixture of PVB and mannitol.

Description

The invention relates to a soft ferrite material (soft magnetic Ferrite material) for the manufacture of devices for shielding electromagnetic frequencies, for example wire coil inductors and Chip components, the chip inductors and chip beads (-ribs or -wül ste) include. The invention also relates to a method of manufacture development of an inductor using the ferrite material. The invention relates in particular to a Ni-Cu-Zn soft ferrite material and to Method of manufacturing a wire coil or chip type inductor using the ferrite material where a low temperature Sintering is possible, the fluctuations in the electromagnetic eigen are low when exposed to external stress (stress) and which has improved electromagnetic properties.

The tremendous progress recently in the field of electronics and Communication devices led to the development of miniaturized, thin and easily installable electronic components, creating a new industrial structure emerged. This led to new problems with gaming as an environmental pollution and communication disruptions that used to be  were careful. Because of the generalization of wireless communication Devices and the multitechnology environment, especially the electro magnetic pollution increases. Therefore, the states of the world are over have come up with the rules to prevent electromagnetic To tighten environmental pollution (FCC, CISPR, VDE, MIL).

Therefore, there has been a demand for a prevention device exposure to electromagnetic waves (EMI / EMC). Consequently the demand for electronic components has increased and that of current technical trend is towards diversification of functions, increasing density and achieving high levels of efficiency.

In addition, the application of the soft ferrite material for use for the production of electronic components such as devices for Prevention of electromagnetic pollution and energy transmission Facilities finely divided depending on the properties, the fre quenz tapes and the like

The manufacturing process also turns away from the conventional one Determine powder metallurgy process and recently become components stacked type and examined in practice det. This method has proven itself in the technical field of klei NEN chip components, e.g. B. the electronic ceramic components as a main area.

Generally, the soft ferrite material required to manufacture small chip components, for example chip inductors, chip beads (Ribs or beads), chip arrangements, chip LC filters and chip trans, high inductance is used. This soft ferrite material includes Mn Zn ferrite, Ni ferrite, Ni-Zn ferrite and Ni-Cu-Zn ferrite.  

The Mn-Zn ferrite has a high permeability and low energy losses on. It is therefore used as a magnetic core for power supply network trans formers and high-voltage line filters and the like. The Mn-Zn However, ferrite has a low radio frequency (high frequency) characteristic and therefore cannot be used for a frequency band of over 1 MHz will. Currently the magnetic core materials are in the frequency band of over 1 MHz can be used, the Ni ferrite, the Ni-Zn ferrite and the Ni-Cu-Zn ferrite.

The conventional method of making a soft ferrite material is as follows: a sintering process is carried out at a temperature of 1000 to 1400 ° C for 1 to 5 hours. The inner electrodes of the elec tronic components, such as the chip inductor and the chip Pearl filters, however, are made of silver (Ag). The above given sintering temperature exceeds the melting point of Ag (960 ° C). Des not only is the sintering temperature too high, but the one produced Components also have high losses in the general frequency band from 500 KHz to 20 MHz. Therefore, the required inductance cannot aims to be. To lower the sintering temperature for the soft ferrite material, will therefore generally be the particle size of the magnetic core material finely crushed down to 0.01 to 1 µm. In this way it is achieved that Energy level of the particles reaches the ground state (metastable state) and the material that moves in the space between the particles becomes increased during sintering so as to promote sintering so that a never temperature sintering can be carried out.

The manufacturing process in which you can go back to fine grinding grips, but requires expensive equipment and a complicated process what causes the manufacturing cost to increase. There is also a pro blem in relation to practical application.  

As another example, there is a method using a component such as B ₂ O ₃ (Japanese Patent Application Laid-Open No. Sho-64-45771). There is still another method in which the sintering is carried out by adding a flux such as ZnO or V ₂ O ₅ to cause surface enlargement of the particles (Japanese Patent Application Laid-Open No. Sho-60-210572).

In the process in which a compound with a low melting point is too is given is the behavior of the co-component with respect to the verb However, the frequency properties are inhibited, which reduces the sintering effect is reduced. In addition, the additives are in this process with ei ner temperature below the sintering temperature of the soft ferrite material as Matrix in the liquid phase. That is why the additives are on the grain borders to promote sintering. Because of the segregation of the Zu therefore there is often a drop in inductance and losses. Furthermore they interact with or expand the inner electrode made of Ag on the Ag electrode. As a result, the magnetic are inherent shafts (the inductance, the Q factor) of the chip inductor affects what has the consequence that the product reliability is worse.

The present invention aims at the disadvantages described above conventional methods are overcome.

The aim of the present invention is therefore a Ni-Cu-Zn soft ferrite material provide, in which the added composite glass powder (Mixing glass powder) even after reacting with the main component of the Matrix a minimal impairment of the electromagnetic properties result and have no interaction with the inner Ag electrode, so that the stability of the inner electrode at a low sintering temperature rature can be guaranteed, and improved properties at one Frequency band from 500 KHz to 20 MHz can be ensured.  

Another object of the invention is a method of manufacture of wire coil inductors and chip inductors at a low sinter temperature by using the Ni-Cu-Zn soft ferrite material.

In order to achieve the above-mentioned goals, the Ni-Cu-Zn soft ferrite material according to the invention for the production of inductors comprises a starting material which (in mol%) consists of 49.0 to 50.0% Fe ₂ O ₃ to 13% CuO, 7.5 to 25% NiO and 12 to 38.5% ZnO, the soft ferrite material also (in% by weight) 0.05 to 15.0% B ₂ O ₃ -Bi ₂ O ₃ -ZnO glass contains.

According to another aspect of the invention, the Ni-Cu-Zn soft ferrite material for producing inductors according to the present invention comprises a starting material which (in mol%) consists of 49.0 to 50.0% Fe ₂ O ₃ , 5 to 13% CuO, 7.5 to 25% NiO and 12 to 38.5% ZnO, the soft ferrite material also (in% by weight) one or more compounds selected from the group consisting of 2, 0% or less CoO, 2.0% or less Co ₂ O ₃ and 2.0% or less Co ₃ O ₄ ; and 0.05 to 15.0% B ₂ O ₃ -Bi ₂ O ₃ -ZnO glass contains.

In another aspect, the present invention relates to a method of manufacturing a wire coil inductor according to the invention, which comprises the following steps:
Add 0.05 to 15.0% by weight of B ₂ O ₃ -Bi ₂ O ₃ -ZnO glass to a starting material which (in mol%) consists of 49.0 to 50.0% Fe ₂ O _3, 5 to 13% CuO, 7.5 to 25% NiO and from 12 to 38.5% of ZnO,
and crushing and drying the same to form a dried powder;
Mixing the dried powder with 5 to 15% by weight of a binder containing 5 to 10% by weight of a main ingredient and 5 to 16% by weight of a reaction inhibitor therein, and producing coarse particles from the mixture; and
Forming using the coarse particles and sintering at a temperature of 860 to 910 ° C.

According to a further aspect, the present invention relates to a method for producing a wire coil inductor according to the invention, which comprises the following stages:
Adding 0.05 to 15.0 B ₂ O ₃ -Bi ₂ O ₃ -ZnO glass to a ferrite powder which (in mol%) consists of 49.0 to 50.0% Fe ₂ O ₃ , 5 to 13% CuO, 7.5 to 25% NiO and 12 to 38.5% ZnO and crushing and drying them to form a dried powder;
Mixing the dried powder with one or more compounds selected from the group consisting (in% by weight) of 2.0% or less CoO, 2.0% or less Co ₂ O ₃ and 2.0% or less Co ₃ O ₄ and calcining the mixture;
Mixing the calcined powder with 5 to 15% by weight of a binder containing 5 to 10% by weight of a main ingredient and 5 to 16% by weight of a reaction inhibitor therein, and producing coarse particles from the mixture; and
Forming using the coarse particles and sintering at a temperature of 860 to 910 ° C.

According to a still further aspect, the present invention relates to a method for producing a chip inductor according to the present invention, which comprises the following stages:
Add 0.05 to 15.0% B ₂ O ₃ -Bi ₂ O ₃ -ZnO glass to a ferrite powder which (in mol%) consists of 49.0 to 50.0% Fe ₂ O ₃ , 5 to 13% CuO, 7.5 to 25% NiO and 12 to 38.5% ZnO and crushing and drying them to form a dried powder;
Adding a binder to the dried powder in a ratio of 1: 1 to 1: 4 and pouring a variety of green sheets using a Doctor method;
Stacking a plurality of the green plates (layers), printing an inner Ag electrode onto the stacked plates (layers), stacking a plurality of the green plates (layers) again, and sintering and shaping an outer electrode on the sintered body.

According to a further aspect, the present invention relates to a method for producing a chip inductor according to the invention, which comprises the following stages:
Mixing a starting material consisting (in mol%) of 49.0 to 50.0% Fe ₂ O ₃ , 5 to 13% CuO, 7.5 to 25% NiO and 12 to 38.5% ZnO, with one or more compounds selected from the group consisting (in% by weight) of 2.0% or less CoO, 2.0% or less Co ₂ O ₃ and 2.0% or less Co ₃ O ₄ ; and with 0.05 to 15.0% B ₂ 0 ₃ -Bi ₂ O ₃ -ZnO glass and crushing and drying the same to form a dried powder;
Adding a binder to the dried powder in a ratio of 1: 1 to 1: 4 and pouring a variety of green sheets using a Doctor method;
Stacking a plurality of the green plates (layers), printing an inner Ag electrode on the stacked plates (layers), renewed stacking a plurality of the green plates (layers) and sintering at a temperature of 880 to 910 ° C .; and
Form an outer electrode on the sintered body.

The invention is based on preferred embodiments described here.

In general, soft ferrite materials (soft magnetic ferrite materials) differ in their properties compared to frequency bands depending on their structure and their composition. The present invention relates to a soft magnetic Ni-Cu-Zn ferrite in which the ZnO component is relatively high and the NiO component is relatively low, which is suitable for a frequency band from 500 KHz to 20 MHz. The basic composition is preferably a starting material which (in mol%) consists of 49.0 to 50.0% Fe ₂ O ₃ , 5 to 13% CuO, 7.5 to 25% NiO and 12 to 38.5% ZnO. The composition particularly preferably also contains a compound selected from the group consisting of 2.0% each of CoO, Co ₂ O ₃ and Co ₃ O ₄ .

In addition, according to the invention, a B ₂ O ₃ -Bi ₂ O ₃ -ZnO glass is added in an amount of 0.05 to 15.0% by weight of the mixture described above.

The addition of the above-mentioned glass has the advantage that the Deterioration of the electromagnetic properties even after the re action can be minimized with the soft magnetic matrix. Especially there is no reaction with an internal electrode in the case of a chip inductor from Ag up and the sintering temperature is reduced, this further Advantages are.

When the glass is added in an amount of 0.05 to 15.0% by weight, the sintering temperature of the matrix can be varied from the conventional temperature of 1000 to 1350 ° C (which is the sintering temperature in the event that a conventional compound with a low melting point (Bi ₂ O ₃ or V ₂ O ₅ ) is used) can be reduced to 860 to 910 ° C. In addition, in this case, the stress (stress) which occurs during the shrinkage of the matrix and the inner electrode after the sintering can be reduced, so that the inner electrode can be stabilized.

The glass should preferably be contained in amounts of 10 to 40% by weight of B ₂ O ₃ , 20 to 40% by weight of Bi ₂ O ₃ and 20 to 70% by weight of ZnO.

Especially in the case of the wire coil inductor using the soft ferrite material according to the invention is produced by the Ver keeping the glass within the matrix increases the sintered density of the matrix. In as a result, the mechanical strength can be improved and due to  the high surface density will adhere to foreign materials during prevents electroplating, which improves the manufacturing yield sert.

In the case of the inductor using the invention Soft ferrite material is made, the particle size should be added NEN glass preferably 0.1 to 10 microns. In particular, the Particle size of the glass is 0.2 to 5 microns in order to grow large prevent large grains as a result of the divergent distribution of the matrix.

The following is the method of manufacturing a wire coil inductor using the dried powder containing the glass according to of the present invention described in more detail.

In the case of the wire coil inductor, be immediately after drying of the powder containing the glass 5 to 15% by weight of a binder with 5 up to 10 wt .-% of a main component and 5 to 16 wt .-% ent added reaction inhibitor and then coarse particles educated. The main ingredient can be any common material, such as is commonly used in the manufacture of a sintered core. At for example, polyvinyl alcohol (PVA) or methyl cellulose can be used the. The task of the reaction inhibitor is to agglomerate the soft to prevent magnetic particles and this material can be mannitol or Propylene glycol (PEG).

The dried powder can be calcined as usual and the Calcination temperature should preferably be 650 to 880 ° C. In particular in particular, the calcination temperature should be 700 to 850 ° C.

Then the calcined powder is processed into coarse particles and it becomes a molding is carried out, whereby the desired shaped body is obtained. The molded body is sintered at a temperature of 860 to 910 ° C. at which  it is a temperature much lower than the one like it is commonly used when a common low connection Melting point is included. During the sintering, the temperature is in tervall from 750 to 900 ° C the one at which the granules are aligned and be made denser. Therefore, when the temperature is abrupt is increased, pores or cavities arise, which lead to the fact that the Per meability decreases and that the quality factor gets worse. Preferred two An abrupt rise in temperature should therefore be avoided. So should, for example, in the above-mentioned temperature interval of the tempera increase preferably at a rate of about 10 ° C / min be performed.

After reaching the sintering temperature, the sintering temperature also becomes preferably maintained for 2 to 3 hours. Then during the Inter Avoid abrupt cooling down to 700 ° C. If an abrupt t cooling down during this interval, the CuO Component from the matrix, which means that the electromagnetic properties deteriorate. Therefore, you should work carefully and during this cooling interval, the cooling Speed is preferably about 5 ° C / min or less.

According to the invention, the microstructure is very strongly stabilized and the following properties: that is, the quality factor is 150 or more, the peak range is 100 KHz to 20 MHz and the inductance is 10 µH or more. In this way, a soft ferrite material can be used improved electromagnetic properties at a low temperature rature can be obtained compared to the conventional method. After standing the method for producing a chip inductor under Ver use of a dried powder with the above-mentioned added Glass described in more detail.  

A binder in the form of a high molecular weight organic compound, such as PVB, methyl cellulose (MC), oleic acid, propylene glycol, toluene or mannitol added to the dried powder in a ratio of 1: 1 to 1: 4. Then green slabs are cast using the Doctor process rens and then a large number of green sheets (layers) are stacked on top of each other stacks. Then an inner Ag electrode is printed on and then one Many of the green sheets (layers) were stacked again. Then the structure sintered at a temperature of 880 to 910 ° C. The sintered temperature from 880 to 910 ° C is a much lower value than the usual value. Then an outer electrode is formed on the sintered body, whereby the Chip inductor according to the invention is obtained.

The invention is described in more detail below using current examples ben, but is not limited to this.

example 1

The starting materials in the compositions of Table 1 below were weighed. These raw materials were put in a polyurethane flask and then crushed, and the mixing was carried out after adding distilled water in an amount 1 to 34 times the amount of the raw materials using YTZ balls (Y ₂ O ₃ -Zirkioniumoxid-balls) until the average particle size was 1 to 1.5 microns. After the mixing was completed, the calcination was carried out at a temperature of 700 to 850 ° C for 2 to 3 hours. Then comminution was carried out again within the same flask. During the re-grinding, a 10B ₂ O ₃ -65Bi ₂ O ₃ -25ZnO glass powder was added to the calcined powder, and the re-grinding was carried out for 24 to 48 hours. When the particle size was reduced to 0.1 to 1.5 µm, drying was carried out using a dryer until the moisture content was 0.2 to 0.7% by weight per unit weight of the raw materials.

The dried powder was classified into a uniform particle size from 60 to 80 mesh and then 5 to 15% by weight of a binder was added given in which 5 to 10 wt .-% polyvinyl alcohol (PVA) and 5 to 16 wt .-% Mannitol were solved. Then the powder was washed using a 50- mesh sieves classified into a uniform particle size and it became a ring-shaped core with an outer diameter of 25 mm, an inner diameter of 18 mm and a height of 4.5 mm made from it. Then the structure produced was sintered. During the sintering, the Temperature increased to about 420 ° C at a rate of about 2 ° C / min and this temperature was maintained for about 4 hours, resulting in a Binder removal was performed.

Then the temperature rose to 750 ° C at a rapid rate speed of about 3 ° C / min and then up to a temperature from 900 ° C the temperature increase at a speed of about 1 ° C / min. When the temperature reached 900 ° C, it became 2 to Maintained for 3 hours and then cooling was performed. In the Cooling was carried out at a rate of 3 ° C / min to cooled down to 700 ° C and then at a rate of 10 ° C / min further cooled down to room temperature.

Then an enamelled (glazed) copper wire was placed on the sintered structure with a diameter of 0.55 mm wound in 20 windings. After that were the inductance and the quality factor (Q factor) at one frequency band from 10 KHz to 40 MHz measured using an HP4291A Network analyzer. The results are shown in Table I below give.

In Table I below, in the conventional example, a sine tion at about 950 ° C.  

Table I

As indicated in Table I above, in the case of the invention Examples 1 to 9 in which the conditions according to the invention are met confirmed that low temperature sintering was possible. Furthermore the inductance value was more than 10 pH and the quality factor Q was about 150. They thus showed improved electromagnetic properties on. That is, through these properties of the material according to the invention it was possible to sinter at a much lower temperature, around 50 up to 100 ° C lower. In addition, the losses were after Sintering much less.

In the case of comparative examples 2 to 6, no glass was added, but a Bi ₂ O ₃ additive or V ₂ O ₅ additive was added. The sintering could therefore not be carried out sufficiently at the low temperature, and this resulted in a low quality factor and a low inductance. The reason for this is that grain boundary diffusion cannot occur if only the Bi ₂ O ₃ or V ₂ O ₅ component is present. In the case of Comparative Example 1, in which the compositions fundamentally differ from the present invention, the quality factor was too low due to the low-temperature sintering, and therefore the electromagnetic properties were inferior.

Example 2

To determine the electromagnetic properties depending on the types of To determine glass, glasses with different physical Properties as given in Table II below, starting material s with the same composition as in Example 1 added. Then was which the respective materials are shaped into annular bodies and sintered. The electromagnetic properties were then determined and the Er Results are shown in Table III below. Before the messun enamelled (glazed) copper wire with a diameter of 0.55 mm wound in 20 turns on the ring-shaped body and there  after the measurement was made using an HP4194A impedance Analyzer performed.

Table II

Table III

From Tables II and III it can be seen that the electromagnetic properties of the soft ferrite material produced varied greatly depending on the variation in the composition of the glass, which leads to the fact that the deformation temperature and the thermal expansion of the glass should be made different . That is, in the case of games 8 and 10 to 15 according to the invention, in which materials a to d according to the invention were used and in which the glass consisted of 10 to 40% B ₂ O ₃ , 20 to 70% Bi ₂ O ₃ and 20 to 40% ZnO to meet the conditions of the present invention, it was seen that the value for the inductance at the commercial frequency was 15 pH or more, the quality factor was 150 or more, and the quality factor peak band (Q Peak band) was 100 kHz to 20 MHz in all examples.

On the other hand, in the cases of Comparative Examples 7 to 9, in which B ₂ O ₃ - SiO ₂ glasses (comparison materials AC) were used, either the inductance value was too low or the quality factor was too low, so that the electromagnetic Properties were worse.

Example 3

Materials with the composition given in Table I were used tongues processed into powders using the procedure of the example 1. Then a PVB mannitol binder was used in a ratio of 1: 1 to 1: 4 admitted. Then the mixture was classified into particles with a uniform size using a 200-325 mesh screen. Then were Green plates (layers) with a thickness of 10 to 200 µm cast under An application of the Doctor procedure.

A large number of the cast green sheets (layers) were placed on top of one another, an inner Ag electrode was placed on the superimposed plates (Layers) were printed and then a large number of the green sheets (layers) laid on top of each other again. Thereafter, sintering was carried out at a temperature of  880 to 910 ° C for 1 to 3 h. Then an outer electrode formed on the sintered body, thereby completing a chip inductor de. In a large number of chip inductors produced in this way which determines the electromagnetic properties using a HP4192A network analyzer and the measured results are in the Table IV below.

Table IV

As can be seen from Table IV above, in the cases of the invention according to Examples 16 to 22, the ge conditions according to the invention sufficient, low-temperature sintering possible. The value was also for the inductance of the soft ferrite material after sintering more than 140 nH and the quality factor Q was 34 or more. This confirmed that they had improved electromagnetic properties. That is, the Chip inductor according to the invention had advantages over a conventional tional chip inductor, which the glass and the co-additives not at all were added. That is, the sintering temperature according to the invention reduced by 50 to 100 ° C and the losses after sintering were significant fictionally low.

According to the invention described above, the sintering is satisfactory descriptive extent even at a low temperature, so that a Soft ferrite material with improved electromagnetic properties can be held. In addition, the production of this material existing systems can be used as they are. An investment tion in expensive systems is therefore not necessary and the difficulties the operation of such systems can be avoided. Therefore can invent according to a soft ferrite material for chip inductors at low cost getting produced.

While the invention has been described above with reference to specific be preferred embodiments explained in more detail, but it is for the expert it goes without saying that it is by no means limited to this, but that these can be changed and modified in many ways without thereby leaving the scope of the present invention.

Claims (23)

1. Ni-Cu-Zn soft ferrite material for the production of inductors, characterized in that it comprises a starting material consisting (in mol%) of 49.0 to 50.0% Fe ₂ O ₃ , 5 to 13% CuO, 7.5 to 25% NiO and 12 to 38.5% ZnO, the soft ferrite material also (in% by weight) 0.05 to 15.0% B ₂ O ₃ - Bi ₂ O ₃ -ZnO -Glass contains. 2. Ni-Cu-Zn soft ferrite material according to claim 1, characterized in that it is also (in wt .-%) one or more compounds selected from the group consisting of 2.0% or less CoO, 2.0% or less of Co ₂ O ₃ , and 2.0% or less of Co ₃ O ₄ . 3. Ni-Cu-Zn soft ferrite material according to claim 1 and / or 2, characterized in that the glass (in wt .-%) consists of 10 to 40% B ₂ O ₃ , 20 to 40% Bi ₂ O ₃ and 20 to 70% ZnO. 4. A method for producing a wire coil inductor, characterized in that it comprises the following stages:
Add 0.05 to 15.0% by weight of B ₂ O ₃ -Bi ₂ O ₃ -ZnO glass to a starting material consisting (in mol%) of 49.0 to 50.0% Fe ₂ O _3, 5 to 13% CuO, 7.5 to 25% NiO and from 12 to 38.5% of ZnO, and crushing and drying the same to form a dried powder;
Mixing the dried powder with 5 to 15% by weight of a binder containing 5 to 10% by weight of a main component and 5 to 16% by weight of a reaction inhibitor therein to form a mixture and to prepare coarse particles from the Mixture; and
Perform shaping using the coarse particles and
Carry out sintering at a temperature of 860 to 910 ° C. 5. The method according to claim 4, characterized in that the ferrite powder also contains (in wt .-%): one or more compounds selected from the group consisting of 2.0% or less CoO, 2.0 % or less Co ₂ O ₃ and 2.0% or less Co ₃ O ₄ . 6. The method according to at least one of claims 4 and / or 5, characterized in that the glass (in wt .-%) consists of 10 to 40% B ₂ O ₃ , 20 to 40% Bi ₂ O ₃ and 20 to 70 % ZnO. 7. The method according to claim 6, characterized in that the glass has a particle size in the range of 0.1 to 10 µm. 8. The method according to claim 7, characterized in that the glass has a particle size in the range of 0.2 to 5 µm. 9. The method according to at least one of claims 4 to 8, characterized ge indicates that the powder calci at a temperature of 650 to 880 ° C. is renated. 10. The method according to at least one of claims 4 to 9, characterized ge indicates that the sintering temperature is maintained for less than 5 hours will hold. 11. The method according to at least one of claims 4 to 10, characterized ge indicates that during the sintering a temperature increase over a Temperature interval from 750 to 900 ° C at a speed of about 10 ° C / min or less is performed and cooling down to 900 700 ° C at a rate of about 5 ° C / min or less becomes.   12. The method according to at least one of claims 4 to 11, characterized ge indicates that the main ingredient mentioned is polyvinyl alcohol or Me is ethyl cellulose. 13. The method according to at least one of claims 4 to 12, characterized ge indicates that the reaction inhibitor mentioned mannitol or propylene glycol col is. 14. A method for producing a chip inductor, characterized in that it comprises the following stages:
Add 0.05 to 15.0% by weight of B ₂ O ₃ -Bi ₂ O ₃ -ZnO glass to a starting material which (in mol%) consists of 49.0 to 50.0% Fe ₂ O _3, 5 to 13% CuO, 7.5 to 25% NiO and from 12 to 38.5% of ZnO, and crushing and drying the same to form a dried powder;
Adding a binder to the dried powder in a ratio of 1: 1 to 1: 4 and pouring a variety of green sheets using a Doctor method;
Stacking a plurality of said green sheets (layers) on top, printing an inner Ag electrode onto the stacked sheets (layers), stacking a plurality of green sheets (layers) again and carrying out sintering; and
Form an outer electrode on the sintered body. 15. The method according to claim 14, characterized in that the said ferrite powder also contains (in wt .-%): one or more compounds selected from the group consisting of 2.0% or less CoO, 2nd , 0% or less Co ₂ O ₃ and 2.0% or less Co ₃ O ₄ . 16. The method according to claim 14 and / or 15, characterized in that said glass (in wt .-%) consists of 10 to 40% B ₂ O ₃ , 20 to 40% Bi ₂ O ₃ and 20 to 70% ZnO . 17. The method according to claim 16, characterized in that the glass has a particle size in the range of 0.1 to 10 µm. 18. The method according to claim 17, characterized in that the glass has a particle size in the range of 0.2 to 5 µm. 19. The method according to at least one of claims 14 to 18, characterized characterized in that the powder at a temperature of 650 to 880 ° C. is calcined. 20. The method according to at least one of claims 14 to 19, characterized characterized in that the sintering temperature is maintained for less than 5 h becomes. 21. The method according to claim 20, characterized in that the sinter temperature is maintained for 1 to 3 hours. 22. The method according to claim 21, characterized in that during sintering a temperature increase over a temperature interval of 750 to 900 ° C at a rate of about 10 ° C / min or less is carried out and cooling from 900 to 700 ° C with a Ge speed of about 5 ° C / min or less is carried out. 23. The method according to at least one of claims 14 to 22, characterized characterized in that a mixture of PVB and mannitol ver is applied.